Rectangular Spacing: An Economic Benefit?

Many loblolly pine (Pinus taeda L.) plantations are established at row spacings of 8 to 12 feet, but some compa-nies are now using rows spaced 14 to 18 feet apart. Wide rows reduce establishment costs when sites are bedded, ripped, ormachine planted. The cost of chemicals is also reduced when treatments are applied in bands along the row. A growth andyield program (Ptaeda2.1V) was used to predict volume losses from planting in 14- to 20-foot rows. Results suggest thatwhen a thinning (to a constant basal area) is conducted at age 15, a rectangularity ratio of 2:1 reduces the amount ofsawtimber predicted at age 23 by only 1 to 2 percent when compared to a square spacing. The cost savings associated withwider rows results in a slight increase in net present value (NPV). Field trials are needed to verify the biological effects ofwide rows on volume growth and branch size of plantations established with less than 600 trees per acre.